configured to use specific gateway locators for indirect access
   through new naming schemes.

BNF of Generic URI Syntax

   This is a BNF-like description of the URI syntax. at the level at
   which specific schemes are not considered.

   A vertical line "|" indicates alternatives, and [brackets] indicate
   optional parts.  Spaces are represented by the word "space", and the
   vertical line character by "vline".  Single letters stand for single
   letters.  All words of more than one letter below are entities
   described somewhere in this description.

   The "generic" production gives a higher level parsing of the same
   URIs as the other productions.  The "national" and "punctuation"
   characters do not appear in any productions and therefore may not
   appear in URIs.

     fragmentaddress        uri [ # fragmentid ]

     uri                    scheme :  path [ ? search ]

     scheme                 ialpha

     path                   void |  xpalphas  [  / path ]

     search                 xalphas [ + search ]

     fragmentid             xalphas




 
RFC 1630                      URIs in WWW                      June 1994



     xalpha                 alpha | digit | safe | extra | escape

     xalphas                xalpha [ xalphas ]

     xpalpha                xalpha | +

     xpalphas               xpalpha [ xpalpha ]

     ialpha                 alpha [ xalphas ]

     alpha                  a | b | c | d | e | f | g | h | i | j | k |
                            l | m | n | o  | p | q | r | s | t | u | v |
                            w | x | y | z | A | B | C  | D | E | F | G |
                            H | I | J | K | L | M | N | O | P |  Q | R |
                            S | T | U | V | W | X | Y | Z

     digit                  0 |1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9

     safe                   $ | - | _ | @ | . | &

     extra                  ! | * | " |  ' | ( | ) | ,

     reserved               = | ; | / | # | ? | : | space

     escape                 % hex hex

     hex                    digit | a | b | c | d | e | f | A | B | C |
                            D | E | F

     national               { | } | vline | [ | ] | \ | ^ | ~

     punctuation            < | >

     void

      (end of URI BNF)

BNF for specific URL schemes

   This is a BNF-like description of the Uniform Resource Locator
   syntax.  A vertical line "|" indicates alternatives, and [brackets]
   indicate optional parts.  Spaces are represented by the word "space",
   and the vertical line character by "vline".  Single letters stand for
   single letters.  All words of more than one letter below are entities
   described somewhere in this description.






 
RFC 1630                      URIs in WWW                      June 1994


   The current IETF URI Working Group preference is for the prefixedurl
   production. (Nov 1993. July 93: url).

   The "national" and "punctuation" characters do not appear in any
   productions and therefore may not appear in URLs.